Abstract
A LIDAR device for scanning a scanning area with the aid of at least two consecutively generated beams, in terms of time, including at least one radiation source for generating and emitting the at least two beams in a pulse-pause pattern in the direction of the scanning area, and including at least one detector for receiving at least two beams scattered and/or reflected on an object, the at least two generated beams being differently polarizable by a polarization encoder, and the detector including a polarization analyzer, which compares the scattered and/or reflected beams to a defined polarization sequence, and, in the event of an agreement of the polarization sequence of the at least two scattered and/or reflected beams with the defined polarization sequence, transmits the at least two reflected beams. Also described is a method for operating a
Claims
1-9. (canceled)
10. A LIDAR device for scanning a scanning area with at least two consecutively generated beams, comprising: at least one radiation source to generate and emit the at least two beams in a pulse-pause pattern in the direction of the scanning area; and at least one detector to receive at least two beams scattered and/or reflected on an object; wherein the at least two generated beams are differently polarizable by a polarization encoder, wherein the at least one detector includes a polarization analyzer to compare the scattered and/or reflected beams to a defined polarization sequence, and wherein, in the event of an agreement of the polarization sequence of the at least two scattered and/or reflected beams with the defined polarization sequence, the at least two scattered and/or reflected beams are transmitted for detection.
11. The LIDAR device of claim 10, wherein the polarization encoder incrementally changes the polarization vectors of the at least two generated beams.
12. The LIDAR device of claim 10, wherein the polarization encoder continuously changes the polarization vectors of the at least two generated beams.
13. The LIDAR device of claim 10, wherein the polarization encoder includes a polarization rotator.
14. The LIDAR device of claim 10, wherein the radiation source clocks a duration of the pauses and a duration of the pulses to be equally or differently long.
15. The LIDAR device of claim 10, further comprising: a polarizing beam splitter, which splits the at least one reflected beam into different polarization components and guides them onto separate detectors, downstream from the polarization analyzer.
16. The LIDAR device of claim 10, wherein the polarization analyzer includes a polarizing beam splitter.
17. A method for operating a LIDAR device for scanning a scanning area with at least one beam, the method comprising: generating at least two beams in the form of a pulse pattern; deflecting the at least two pulses along a horizontal scan angle and along a vertical scan angle; assigning a specific polarization direction to the at least two pulses; and guiding, at least one pulse, having the specific polarization direction which is scattered or reflected on an object, by a polarization analyzer onto at least one detector; wherein the LIDAR device includes: at least one radiation source to generate and emit the at least two beams in a pulse-pause pattern in the direction of the scanning area; and the at least one detector to receive at least two beams scattered and/or reflected on an object; wherein the at least two generated beams are differently polarizable by the polarization encoder, wherein the at least one detector includes the polarization analyzer to compare the scattered and/or reflected beams to a defined polarization sequence, and wherein, in the event of an agreement of the polarization sequence of the at least two scattered and/or reflected beams with the defined polarization sequence, the at least two scattered and/or reflected beams are transmitted for detection.
18. The method of claim 17, wherein an identical polarization direction is assigned to multiple consecutive pulses before the specific polarization direction is changed by the polarization encoder.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 shows a schematic representation of a LIDAR device according to a first exemplary embodiment.
[0021] FIG. 2 shows a schematic representation of a LIDAR device according to a second exemplary embodiment.
[0022] FIG. 3 shows a schematic representation of a LIDAR device according to a third exemplary embodiment.
[0023] FIGS. 4a and 4b show examples of generated and encoded pulse patterns.
[0024] FIGS. 5a and 5b show the received intensity distribution of the LIDAR device according to the second exemplary embodiment.
DETAILED DESCRIPTION
[0025] FIG. 1 shows a schematic representation of a LIDAR device 1 for scanning a scanning area with the aid of at least two consecutively generated beams 2 according to a first exemplary embodiment. LIDAR device 1 includes a radiation source 4, which is an infrared laser 4, for example. Radiation source 4 generates beams 2 or laser beams 2 in the form of pulses 2. In particular, the radiation source generates at least two consecutive beams 2, which together form a pulse pattern. The pulse pattern is, in particular, a pulse-pause pattern since a pause follows each generated beam 2 or pulse 2. After being generated, the generated beams 2 pass a polarization encoder 6. Polarization encoder 6 is made up of, in particular, a linear polarization rotator and a corresponding activation or evaluation logic. In this way, the polarization rotator may be rotated differently and thus create an additional encoding in the form of an individual polarization for each pulse 2, in addition to the pulse-pause pattern. Encoded beams 8 may subsequently be deflected in a controlled manner by a pivotable mirror 10 along a vertical scan angle and a horizontal scan angle, and thus expose or scan a scanning area. As an alternative, instead of a movable mirror 10, it is also possible to use a rotatable or pivotable radiation source 4, including a polarization encoder 6 situated in front of radiation source 4, for scanning a scanning area. For example, radiation source 4 and polarization encoder 6 may be situated on a rotor. If an object 12 is present in the scanning area, the generated and encoded beams 8 may be at least partially reflected by this object 12. The encoding is also at least partially maintained in the process. The generated and encoded beams 8 become reflected beams 14 as a result of the reflection on object 12.
[0026] Reflected beams 14 may be received by a polarization analyzer 16. Polarization analyzer 16 is provided upstream from detector 18 and is linked to polarization encoder 6 via data lines 20. Polarization analyzer 16 thus knows the last encoding of the generated pulse pattern assigned to polarization encoder 6. According to the exemplary embodiment, polarization analyzer 16 is a rotatable, linear polarization filter, which may be set or rotated according to the predefined encoding by polarization encoder 6 to be able to transmit reflected beams 14. If the encoding of reflected beams 14 agrees with the specific encoding of polarization encoder 6, reflected beam 14 may pass polarization analyzer 16 in the direction of detector 18 unimpeded. In this way, scattered light 22 or undesirable extraneous irradiation 22 may be blocked by polarization analyzer 16, or at least arrive at detector 18 in weakened form, if irradiation 22 does not have the specific encoding.
[0027] FIG. 2 shows a schematic representation of a LIDAR device 1 according to a second exemplary embodiment. In contrast to LIDAR device 1 according to the first exemplary embodiment, LIDAR device 1 includes a polarizing beam splitter 24, which is provided downstream from polarization analyzer 16. Beams 14 reflected by object 12 may thus pass polarization analyzer 16 unimpeded due to their encoding, and may subsequently be deflected by polarizing beam splitter 24 corresponding to their polarization components of their polarization vector P to a first detector 18 or a second detector 19. According to the exemplary embodiment, polarizing beam splitter 24 splits the linearly polarized reflected beams 14 or the individual reflected pulses 14 corresponding to their horizontally polarized polarization component of their polarization vector P and corresponding to their vertically polarized polarization components. FIGS. 5a and 5b illustrate this principle in detail.
[0028] FIG. 3 shows a schematic representation of a LIDAR device 1 according to a third exemplary embodiment. In contrast to the second exemplary embodiment of LIDAR device 1, polarization analyzer 16 is configured as a polarizing beam splitter 16, 24. A separate polarization analyzer 16, such as is shown in the first exemplary embodiment, for example, may thus be dispensed with. Polarizing beam splitter 16, 24 itself is not able to directly distinguish unencoded beams 22 from encoded reflected beams 14. The two detectors 18, 19 are linked to polarization encoder 6 via data lines 20 and may establish based on the signals received from detectors 18, 19 whether received beams 14, 22 were encoded with the aid of polarization encoder 6. By splitting polarization vectors P of the respective beams 14, 22, polarization vector P of received beams 14, 22 may be reconstructed by a combination of detectors 18, 19. In this way, a polarization direction of the respective beam pulses 14, 22 may also be compared to the polarization directions of the generated beam pulses 8. In the event of an agreement of the polarization directions of the generated beams 8 and of the reflected received beams 14, the corresponding signals are used for further evaluation. All residual signals may remain unconsidered.
[0029] FIG. 4a shows beam pulses 2 generated by way of example, which were encoded with a continuously varied polarization direction or polarization vector P. Pulses 2 here were provided with a polarization with the aid of a rotatable linear polarization filter of polarization encoder 6 of LIDAR device 1 according to the first exemplary embodiment. The individual beam pulses 2 are plotted in an intensity-time diagram. The horizontal axis corresponds to the intensity. The vertical axis corresponds to a chronological progression. The individual beam pulses 2 have an identical pulse duration tp and an identical pause t, in terms of time, between beam pulses 2. The encoding here takes place via the sequence of the different polarization vectors P which was assigned to the respective beams 2.
[0030] FIG. 4b shows an alternative example of possible beam pulses 2, which were also plotted in an intensity-time diagram. Pulse duration tp of the individual beam pulses 2 is varied by radiation source 4. An assignment of a polarization vector P is carried out by polarization encoder 6 as a function of pulse duration tp. The first two beam pulses 2 in the diagram here are equally long, in terms of time, and have an identical polarization vector P. The further beam pulses 2 are varied in their pulse duration tp and in terms of their polarization vectors P.
[0031] FIGS. 5a and 5b show received intensity distributions of first detector 18 and of second detector 19 of the LIDAR device according to the second exemplary embodiment. Polarizing beam splitter 24 splits received beam pulses 14 into their horizontal and vertical polarization components corresponding to their polarization vectors P. For example, a vertically polarized beam exclusively has vertical polarization components. In this way, for example, only second detector 19 detects a signal. In the case of a polarization vector P extending diagonally, both detectors 18, 19 detect a signal. The received signals or intensities of the signals are dependent on the direction of polarization vectors P.
